The Effect of Hemorrhage on Plasma Iron Turnover

The plasma iron turnover rate in rats following a single hemorrhage reachesa maximum in about 48 hours and returns to normal between the seventh andtenth day. There is considerable variation in individual rats in both the maximum rate attained and the time required for recovery. No significant difference in response was observed due to the severity of hemorrhage uponremoval of 2.7 to 18 per cent of total red cells.

Submitted on June 20, 1960 Accepted on November 20, 1960     

An Assessment of Erythrocyte Lithium Concentrations as a Measure of Patient Compliance

Following oral administration of only one dose of lithium (e.g. just prior to a clinic blood test), plasma concentrations rise quickly and may appear to be in the therapeutic steady state range for several hours. At the clinic, therefore, noncompliance may go undetected. It has been suggested that measurements of erythrocyte lithium concentrations (Le) may be more useful than plasma lithium concentrations (Lp) in detecting patient non-compliance. This was investigated by comparing the pharmacokinetics of lithium in plasma and erythrocytes after a single 800 mg dose of lithium carbonate and during constant dosing around steady state. Twelve healthy male volunteers took part in the study and took 800 mg of lithium carbonate (Priadel) for 28 days. Le and Lp ranges were determined around steady state using data obtained from eight volunteers known to be compliant. Compliance was measured using electronic monitoring. Both erythrocyte and plasma lithium concentrations reached values comparable to steady state after a single oral dose. This suggests that Le measurements are no better than Lp measurements when attempting to identify noncompliant patients who only dose shortly before a blood test.